Compositions And Methods For Selective Deposition Modeling

ABSTRACT

There is provided compositions and methods for producing three-dimensional objects by selective deposition modeling with a polar build material and a non-polar support material. The build material comprises a hydrocarbon wax material and a viscosity modifier, and the support material comprises a hydrocarbon alcohol wax material and a viscosity modifier. After the selective deposition modeling process has been completed, the object can be placed in a bath of polar solvent to remove the support material. The particular materials provided herein, and the post-processing methods associated therewith, provide for improved part quality of the three-dimensional object and for improved post-processing techniques. The three-dimensional objects can subsequently be used in a number of applications, such as patterns for investment casting.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of copending U.S. patent applicationSer. No. 14/041,411, filed on Sep. 30, 2013, which is a continuation ofU.S. Pat. No. 8,575,258, issued on Nov. 5, 2013, which claims thebenefit of U.S. Provisional Patent Application Ser. No. 61/177,365,filed on May 12, 2009, the entireties of which are hereby incorporatedby reference.

FIELD OF THE INVENTION

The present invention is related to compositions and methods forbuilding three-dimensional objects, and more particularly, to wax-basedbuild materials and wax-based support materials, and associatedapparatus and methods, for building three-dimensional objects utilizingsuch materials.

BACKGROUND OF THE INVENTION

Various solid freeform fabrication, or SFF, techniques are commonly usedto produce three-dimensional objects. The various approaches aregenerally characterized by the building up of three-dimensional objectsfrom computer data descriptive of the object in an additive manner froma plurality of formed and adhered layers, each layer representing across-section of the three-dimensional object. Typically, successivelayers of the object are formed and adhered to a stack of previouslyformed and adhered layers. According to one SFF technique, an objectcross-section is formed by selectively depositing an unsolidified,flowable material onto a working surface in desired patterns which willbecome part of the object cross-section, and then allowing or causingthe material to form the object cross-section and simultaneously adhereto a previously-formed object cross-section. These steps are thenrepeated to successively build up the three-dimensional objectcross-section by cross-section. This approach is referred to asselective deposition modeling (SDM) due to the manner in which objectformation occurs.

Typical SDM approaches include Thermal Stereolithography as described inU.S. Pat. No. 5,141,680 to Almquist et al. Also typical of this approachis Fused Deposition Modeling as described in U.S. Pat. Nos. 5,121,329and 5,340,433 to Crump in which a thermosettable material is dispensedwhile in a molten state and then hardens after being allowed to cool.Another example is described in U.S. Pat. No. 5,260,009 to Penn. Anotherexample is Ballistic Particle Manufacturing as described in U.S. Pat.Nos. 4,665,492; 5,134,569 and 5,216,616 to Masters, in which particlesare directed to specific locations to form object cross-sections.

Thermal stereolithography is particularly suitable for use in an officeenvironment because non-reactive, non-toxic materials can be used.Moreover, the process of forming objects using these materials may notrequire the use of radiations (e.g. UV radiation, IR radiation and/orlaser radiation), heating materials to combustible temperatures (e.g.burning the material along cross-section boundaries), reactive chemicals(e.g. photopolymers) or toxic chemicals (e.g. solvents & the like),complicated cutting machinery, and the like, which can be noisy or posesignificant risks if mishandled. Instead, object formation is achievedby heating the material to a flowable temperature then selectivelydispensing the material and allowing it to cool.

A critical problem that exists in relation to thermal stereolithographyand the like involves finding suitable materials that are capable ofbeing dispensed from the dispensers currently used in such systems (suchas an ink jet print head), and which are also capable of formingthree-dimensional objects with suitable strength and accuracy once theyhave been formed. In addition, build materials must be paired withparticular support materials to provide the necessary mechanical supportfor the three-dimensional object to be accurately produced yet allowingfor the finished object to be conveniently and safely separated from thesupport material after the SDM process is complete.

Pattern waxes suitable for use in investment casting are generally notsuitable for SDM processes. These materials tend to have highviscosities, relatively low toughness, or other properties which makesthem difficult to handle and dispense from multi-orifice ink-jetdispensers such as those which may be used in SDM processes. Highmaterial viscosity also reduces the ability to build accurate parts.Previous pattern waxes in the appropriate viscosity range typicallyexhibit relatively high layer to layer distortion. Further, theseprevious materials tend to have latent heat properties that are notsuitable for quick heat dissipation and fast three-dimensional objectbuilding.

For these and other reasons, there is an unmet need for materialssuitable for use in SDM which are capable of being jetted through anappropriate dispenser (such as multi-orifice, ink-jet type print head)and have the toughness, handling, and dimensional stability propertiesappropriate for selective deposition modeling. These materials shouldalso have the properties sufficient for the subsequent use of thethree-dimensional object, for example, as a pattern for investmentcasting processes.

BRIEF SUMMARY OF THE INVENTION

The present invention provides combinations of compositions, as well asassociated apparatus and methods, that include a build material andsupport material for producing three-dimensional objects having materialproperties and dimensional accuracy suitable for various end uses of thethree-dimensional object, including but not limited to investmentcasting.

One exemplary combination of compositions of the present inventionincludes a build material that comprises a build hydrocarbon waxmaterial defining a melting temperature of between about 70° C. andabout 80° C., wherein the build hydrocarbon wax material comprisesbetween 75% and 85% by weight of the build material. An exemplary buildhydrocarbon wax includes paraffin wax. The build material furthercomprises a build viscosity modifier defining a softening temperature ofbetween about 90° C. and about 145° C. and defining a hydrocarbon resinfree of oxygen, wherein the build viscosity modifier comprises between15% and 25% by weight of the build material. An exemplary buildviscosity modifier includes a hydrogenated hydrocarbon resin. The buildmaterial defines a viscosity of between about 11 and about 14 centipoiseat 80° C. and defines a melting temperature of between about 65° C. andabout 85° C. The combination of composition also includes a supportmaterial that comprises a support hydrocarbon alcohol wax materialdefining a melting temperature of between about 52° C. and about 65° C.,wherein the support hydrocarbon wax material comprises between 60% and68% by weight of the support material. Exemplary support hydrocarbonalcohol waxes include octadecanol and hexadecanol. The support materialfurther comprises a support viscosity modifier defining a hydrogenatedrosin that comprises between about 60 and about 200 acid number, whereinthe support viscosity modifier comprises between 32% and 40% by weightof the support material. An exemplary support viscosity modifierincludes a hydrogenated rosin having about 120 acid number. The supportmaterial defines a viscosity of between about 11 and about 14 centipoiseat 80° C.

Another exemplary embodiment of the present invention includes anapparatus for producing three-dimensional objects using the buildmaterial and support material described above. More specifically, theapparatus includes a platform upon which the build material and thesupport material are selectively dispensed, a dispensing device forselectively dispensing the build material and support material, andsupplies for the build material and for the support material forproviding the respective material in a generally flowable state to thedispensing device. A further embodiment of the present inventioncomprises methods for producing a three-dimensional object byselectively dispensing the build material and support material describedabove, allowing the materials to define a generally solid state, andseparating the support material from the build material to provide thethree-dimensional object comprising the solidified build material.

Yet another embodiment of the present invention includes a method forseparating a three-dimensional object produced with build material froma support material used to support the build material during theproduction of the three-dimensional object. The method comprisespositioning the three-dimensional object and the support material in abath of polar solvent and then providing an agitation device thatagitates the bath of polar solvent with respect to the support materialin the bath. The temperature of the polar solvent is controlled to bebetween about 35° C. and about 50° C., and the three-dimensional objectis removed from the bath once substantially all of the support materialhas been removed. This method may further include the removing of whiteresidue from the object, such as by using a solution of 30%glycerin-alcohol or the like.

Still further embodiments of the invention include additional methodsand apparatus for producing and cleaning three-dimensional objectsproduced by selective deposition modeling as disclosed in the detaileddescription below.

BRIEF DESCRIPTION OF THE DRAWING

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawing, which is not necessarily drawn toscale and is meant to be illustrative and not limiting, and wherein FIG.1 is a diagrammatic side view of an SDM apparatus in accordance with oneembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter inwhich some, but not all, embodiments of the invention are described.Indeed, the invention may be embodied in many different forms and shouldnot be construed as limited to the embodiments set forth herein; rather,these embodiments are provided so that this disclosure will satisfyapplicable legal requirements. All patents and applications disclosedthroughout this application are incorporated by reference herein intheir entirety.

The present invention relates to compositions of build materials andsupport materials used to produce three-dimensional objects by selectivedeposition modeling, as well as associated apparatus and methods. Thebuild material and support material are phase change materials that areheated to a flowable state in order to be dispensed by the SDM apparatusand are cooled to define a non-flowable state after dispensing. Once theSDM process has been completed, the build (which typically includes theobject of build material generally surrounded by the support structureof support material) may be removed from the SDM apparatus and placed ina bath of solvent in order for the support material to be removed fromthe object of build material. In some embodiments, the build materialdefines a non-polar material and the support material defines a polarmaterial, such that a polar solvent may be used, with or withoutagitation, to remove the support material without significantlyaffecting the accuracy of the object of build material. These and otheraspects of the various embodiments of the invention will be described inmore detail below.

The term “build material,” “support material,” or “material” as usedherein describes the respective materials dispensed by the dispensingdevice in order to build the three-dimensional object. The buildmaterial includes the materials that constitutes the object being builtby the SFF technique, and the support material includes the materialthat is dispensed to support the object being built and that mayultimately be separated from the object in a post-process operation orthe like. Although the embodiments of the build material and supportmaterial described herein are phase change materials that do not requirecuring in order to return to a non-flowable state, it should beappreciated that further embodiments of the invention may includeadditives in the material(s) that may require curing, such as by a UVsource or the like.

As used herein, the term “a flowable state” of a build material is astate wherein the material is unable to resist shear stresses that areinduced by a dispensing device, such as those induced by an ink jetprint head when dispensing the material, causing the material to move orflow. In certain embodiments of the present invention, the flowablestate of the build material is a liquid state. However, the flowablestate of the build material may also exhibit thixotropic-likeproperties. The term “solidified” and “solidifiable” as used hereinrefer to the phase change characteristics of a material where thematerial transitions from the flowable state to a non-flowable state.

Also as used herein, a “non-flowable state” of a build material is astate wherein the material is sufficiently self-supportive under its ownweight so as to hold its own shape. A build material existing in a solidstate, a gel state, or paste state, are examples of a non-flowable stateof a build material for the purposes herein.

SDM Apparatus

FIG. 1 is a schematic diagram of an SDM apparatus 10 in accordance withcertain embodiments of the present invention. The SDM apparatus 10 isshown building a three-dimensional object 44 on a support structure 46in a build environment 12. The object 44 and support structure 46 arebuilt in a layer by layer manner on a build platform 14 that can beprecisely positioned vertically by any conventional actuation device 16,which in FIG. 1 generally comprises a pneumatic or hydraulic cylinder,but in further embodiments may comprise any actuation device that raisesand lowers the build platform.

Directly above and parallel to the platform 14 is a rail system 18 onwhich a material dispensing trolley 20 resides carrying a dispensingdevice 24. In certain embodiments of the present invention, thedispensing device 24 is an ink jet print head that dispenses a buildmaterial and support material and is of the piezoelectric type having aplurality of dispensing orifices. However, other ink jet print headtypes could be used, such as an acoustic or electrostatic type, ifdesired. Alternatively, a thermal spray nozzle could be used instead ofan ink jet print head, if desired. An example dispensing device 24 isthe piezoelectric Z850 print head. The material dispensed from the Z850print head desirably has a viscosity of between about 11 to about 14centipoise at a dispensing temperature of about 80° C. The dispensingmethodology of this system is described in greater detail in U.S. Pat.No. 6,841,116 assigned to the assignee of the present invention. Furtherembodiments of the present invention comprise alternative dispensingdevices.

The trolley 20 of FIG. 1 carrying the dispensing device 24 is fed thebuild material 22 from a remote reservoir 49. The remote reservoir isprovided with heaters 25 to bring and maintain the build material in aflowable state. Likewise, the trolley 20 carrying the dispensing device24 is also fed the support material 48 from remote reservoir 50 in theflowable state. In order to dispense the materials, a heating device isprovided to initially heat the materials to the flowable state, and tomaintain the materials in the flowable state along its path to thedispensing device. In an example embodiment, the heating devicecomprises heaters 25 on both reservoirs 49 and 50, and additionalheaters (not shown) on the umbilicals 52 connecting the reservoirs tothe dispensing device 24.

Located on the dispensing device 24 are discharge orifices 27M and 27Sfor respectively dispensing build material 30 and support material 31.Discharge orifices 27M and 27S are adapted to dispense their respectivematerials to any desired target location in the build environment 12.

The dispensing device 24 is reciprocally driven on the rail system 18along a horizontal path (i.e., along the X-axis) by a conventional drivedevice 26 such as an electric motor. In some embodiments of the presentinvention, the trolley carrying the dispensing device 24 takes multiplepasses to dispense one complete layer of the materials from dischargeorifices 27M and/or 27S.

Layers 28 are sequentially deposited to form object 44. In FIG. 1, aportion of a layer 28 of dispensed build material 30 is shown as thetrolley has just started its pass from left to right. FIG. 1 shows theformation of an uppermost layer 28. A bottom-most layer 28 (not shown)resides adjacent platform 14. Dispensed build-material droplets 30 andsupport material droplets 31 are shown in mid-flight, and the distancebetween the discharge orifice and the layer 28 of build material isgreatly exaggerated for ease of illustration. In certain embodiments ofthe present invention, the droplets comprise dispensing drops defining adrop mass in the range of between about 40 nanograms and about 60nanograms, or more preferably of about 50 nanograms and the distancefrom the dispensing device 24 to the layer 28 being formed is about 0.5millimeter to about 1.0 millimeter. The layer 28 formed defines a heightof between about 0.015 inches to 0.040 inches, or more preferably ofabout 0.025 inches (the height being defined by the distance between thelower surface of the planarizer and the top surface of the previouslydeposited layer). The layer 28 may be all build material, all supportmaterial, or a combination of build and support material, as needed, inorder to form and support the three-dimensional object.

The build material and support material are dispensed as discrete liquiddroplets in the flowable state, which solidify upon contact with thelayer 28 as a result of a phase change. Alternatively, the materials maybe dispensed in a continuous stream in an SDM apparatus, if desired.Each layer 28 of the object 44 is divided into a plurality of pixels ona bit map, in which case a target location is assigned to the pixellocations of the object for depositing the build material 22. Likewise,pixel coordinates located outside of the object may be targeted fordeposition of the support material 48 to form the supports for theobject 44 as needed. Generally, once the discrete liquid droplets aredeposited on all the targeted pixel locations of the bit map for a givenlayer, the dispensing of material for forming the layer is complete, andan initial thickness of layer 28 is established. In certain embodimentsof the present invention, the initial layer thickness is greater thanthe final layer thickness.

A planarizer 32 is then drawn across the layer to smooth the layer andnormalize the layer to establish the final layer thickness (see FIG. 3,discussed below). The planarizer 32 is used to normalize the layers asneeded in order to eliminate the accumulated effects of drop volumevariation, thermal distortion, and the like, which occur during thebuild process. It is the function of the planarizer to melt, transfer,and remove portions of the dispensed layer of build material in order tosmooth it out and set a desired thickness for the layer. This ensures auniform surface topography and layer thickness for all the layers thatform the three-dimensional object and the support structure. However, itproduces waste material that must be removed from the system. Theplanarizer 32 may be mounted to the material dispensing trolley 20 ifdesired, or mounted separately on the rail system 18 (as shown in FIG.1). Alternatively, the layers can be normalized by utilizing capillaryaction to remove excess material, as disclosed in U.S. Pat. No.6,562,269, assigned to the assignee of the present invention, or anactive surface scanning system that provides feedback data that can beused to selectively dispense additional material in low areas to form auniform layer as disclosed in U.S. Pat. No. 6,492,651, also assigned tothe assignee of the present invention.

A waste collection system (not shown) is used to collect the excessmaterial generated during planarizing. The waste collection system maycomprise an umbilical that delivers the material to a waste tank orwaste cartridge, if desired. A waste system for curable phase changematerials is disclosed in U.S. Pat. No. 6,902,246, assigned to theassignee of the present invention.

A power supply 37 provides electrical power to at least the actuationdevice 16, the planarizer 32, the computer controller 40 (connected toexternal computer 34), the drive device 26, and the dispensing device24, as well as the heaters 25 for initially heating the build materialand support material into a flowable state and the heated umbilicals 52for keeping the respective material in a flowable state. Still furtherfeatures common to SDM apparatus may be provided, including, but notlimited to, a curing device for selectively curing materials that mayinclude photopolymers or photoinitiators as a component in the material.

Build Material

Turning now to the build material of the present invention, the buildmaterial comprises a build hydrocarbon wax and at least one buildviscosity modifier (also known as a tackifier). In order for the buildmaterial to be properly dispensed through the dispensing device in someembodiments of the present invention, the build material defines aviscosity of between about 11 and about 14 centipoise at 80° C., or morepreferably a viscosity of between about 12 and about 13 centipoise at80° C. The build material of some embodiments also defines a meltingtemperature of between about 65° C. and about 85° C.

The build hydrocarbon wax of certain embodiments defines a meltingtemperature of between about 70° C. and about 80° C. Example buildhydrocarbon waxes include, but are not limited to paraffin wax (oneexample being HM Paraffin provided by Koster Keunen LLC.

The build viscosity modifier of certain embodiments defines a softeningtemperature of between about 90° C. and about 145° C., or morepreferably between about 115° C. and about 125° C. The build viscositymodifier of certain embodiments defines a hydrocarbon resin free ofoxygen, such as a hydrogenated hydrocarbon resin (some examples beingArkon P-125, Arkon P-100, Arkon P-90, and combinations thereof, whichare alicyclic hydrocarbon resin tackifiers available from ArakawaChemical Inc.); whereas further embodiments provide alternative buildviscosity modifiers that include, but are not limited to, Foralyn 90Ester of Hydrogenated Rosin and Foralyn 110 Ester of Hydrogenated Rosin,both of which are available from EASTMAN Chemical BV.

Various embodiments of the build material comprise between 75% and 85%by weight of build hydrocarbon wax material and between 15% and 25% byweight of build viscosity modifier. One non-limiting example formulationof build material comprises about 81% build hydrocarbon wax and about19% build viscosity modifier in order to adjust the viscosity of thebuild material to be 12 centipoise at 80° C. The formulations for boththe build material and the support material of certain embodiments ofthe present invention include a variable amount of viscosity modifier inorder that the build material and support material will have particularviscosities in order that they may be dispensed in a controlled andconsistent manner. Therefore, the relative percentage of viscositymodifier will be governed by the desired viscosity for such embodimentsof the present invention.

Still further embodiments of the present invention include buildmaterials that include alternative phase change materials and mayinclude additional materials such as waxes, resins, diluents, fillers,photoinitiators, polymerization inhibitors, and other additives known inthe art.

Support Material

Turning now to the support material of the present invention, thesupport material comprises a support hydrocarbon alcohol wax and atleast one support viscosity modifier. In order for the support materialto be properly dispensed through the dispensing device in someembodiments of the present invention, the support material defines aviscosity of between about 11 and about 14 centipoise at 80° C., or morepreferably a viscosity of between about 12 and about 13 centipoise at80° C.

The support hydrocarbon alcohol wax of certain embodiments defines amelting temperature of between about 52° C. and about 65° C. Examplesupport hydrocarbon alcohol waxes include, but are not limited tooctadecanol and hexadecanol.

The support viscosity modifier of certain embodiments defines ahydrogenated rosin that comprises between about 60 and about 200 acidnumber, or more preferably between about 100 and about 150 acid number,and still more preferably about 120 acid number. Example supportviscosity modifiers include, but are not limited to, tackifiers such asPinecrystal KR-610 available from Arakawa Chemical Inc. or Foralyn Eavailable from Eastman Chemical Company.

Various embodiments of the support material comprise between 60% and 68%by weight of support hydrocarbon alcohol wax material and between 32%and 40% by weight of support viscosity modifier. One non-limitingexample formulation of support material comprises about 65% supporthydrocarbon alcohol wax and 35% support viscosity modifier in order toadjust the viscosity of the support material to be 12.5 centipoise at80° C. Still further embodiments of the present invention includesupport materials that include alternative phase change materials andmay include additional materials such as waxes, resins, diluents,fillers, photoinitiators, polymerization inhibitors, and other additivesknown in the art. Preferably, such alternative and/or additionalmaterials do not adversely affect the ability of the support material tobe removed from the build material during the post-processingoperations.

Post-Processing

After the three-dimensional object has been produced by the SDMapparatus, it should be removed from the support material surroundingthe object. Accordingly, methods for separating the three-dimensionalobject from the support material are provided. The methods includesremoving the three-dimensional object and support material, typicallywhile still connected to the platform, from the SDM apparatus andpositioning the build and platform in a both of polar solvent. Becausethe build material of the three-dimensional object is a non-polarmaterial, it is generally unaffected by the polar solvent. However,because the support material is a polar material, the polar solventcauses the support material to break down and separate from the buildmaterial. The bath may include an agitation device that agitates thesolvent in order to expedite the removal of the support material, andthe temperature of the bath is controlled to be between about 35° C. andabout 50° C., or more preferably between about 42° C. and about 50° C.,which also expedites the removal of the support material. Using thisprocess, relatively small parts, such as jewelry parts, can be cleanedin about 15 to 30 minutes.

The polar solvent provided in the bath can comprise any polar materialand includes, but is not limited to, poly(propylene) glycol, ethanol,91% isopropyl alcohol, and 100% isopropyl alcohol. After thethree-dimensional object has been removed from the bath after thesupport material has been substantially removed, the three-dimensionalobject may have a white residue on its outer surfaces. The object can berinsed with a solution comprising about 30% glycerin-alcohol in order toremove the white residue from the object surfaces. Still furtherpost-processing operations may be undertaken with the object prior toits subsequent use in investment casting or other applications.

EXAMPLES

The following materials are exemplary build material (WM-134A) andsupport material (WS-114B) formulations:

% WM-134A HM Paraffin 76.82 Arkon P-100 17.09 Arkon P-90 6.09 Total 100WS-114B Octadecanol 65 KR-610 35 Total 100

The viscosity of each material is 12 cps at 80° C. The parts built withWM-134A build material and WS-114B support material cleaned with thepost process described above have high resolution and good castabilityfor various metal casting process, including gold, silver, aluminum andsteel alloys, etc. However, it was noticed that the parts built withWM-134A material have relatively narrow post processing window, whichmeans the post processing temperature has to be controlled in arelatively narrow range, otherwise the resolution of the parts,especially for fine feature parts, may be affected. In order to improvepost process window, formulation WM-P125 was developed to include 81% HMParaffin and 19% Arkon P-125 to have a viscosity of 12 cps at 80° C.;and the parts built with WM-P125 (and supported by WS-114B) can becleaned at relatively high temperature without scarifying resolution,which makes post processing window wide and post processing time muchshorter. Further embodiments of the present invention includealternative formulations in order to provide the appropriate partresolution and/or desired process window.

Accordingly, the present invention provides for the production ofthree-dimensional objects with improved build and support materials.Many modifications and other embodiments of the invention set forthherein will come to mind to one skilled in the art to which theinvention pertains having the benefit of the teachings presented in theforegoing descriptions and the associated drawings. Therefore, it is tobe understood that the invention is not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims. It isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents. Although specific terms areemployed herein, they are used in a generic and descriptive sense onlyand not for purposes of limitation.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

That which is claimed:
 1. A method of separating a three-dimensionalobject produced with build material from a support material used tosupport the build material during the production of thethree-dimensional object, the method comprising: positioning thethree-dimensional object and the support material in a bath of polarsolvent; and agitating the bath of polar solvent with respect to thesupport material in the bath.
 2. The method of claim 2 furthercomprising removing a white residue from the three-dimensional object.3. The method of claim 2, wherein removing the white residue comprisesremoving the object from the bath of polar solvent and rinsing theobject with a solution comprising about 30% glycerin-alcohol.
 4. Themethod of claim 1, wherein the bath of polar solvent comprises one ormore of poly(propylene)glycol, ethanol, and isopropyl alcohol.
 5. Themethod of claim 4, wherein the bath of polar solvent comprises 91%isopropyl alcohol.
 6. The method of claim 4, wherein the bath of polarsolvent comprises 100% isopropyl alcohol.
 7. The method of claim 1,wherein the temperature of the polar solvent is controlled to be betweenabout 35° C. and about 50° C.
 8. The method of claim 1, wherein thetemperature of the polar solvent is controlled to be between about 42°C. and about 50° C.